Two siblings, Hyoi and Ryoi, possess the ability to transform into feline creatures. They embark on a mission to decode the enigma behind a multi-armed, encroaching demon outbreak that poses a threat to their fellow pupils. Subsequently, they find themselves facing their former mentor Jukokubo, who holds the reins of mastery over the shadowy feline realm. Whether or not they can vanquish the wickedness he has unleashed onto the world remains to be seen.